Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

761
FXUS63 KLOT 141127
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
627 AM CDT Thu May 14 2026

.KEY MESSAGES...

- Temperatures trend warmer through the weekend and into early
  next week.

- Chances for periodic showers and storms will return to the
  area tonight into early Friday

- Scattered strong storm chances at times this weekend, though
  a good amount of dry time is likely.

- Better shot at more widespread showers and thunderstorms, some
  possibly severe, Monday into Tuesday.

&&

.DISCUSSION...
Issued at 309 AM CDT Thu May 14 2026

Light winds and clear skies, under the influence of surface
high pressure, have set up a chilly mid May morning across the
area. Temperatures are expected to bottom out prior to daybreak
in the upper 30s to the low 40s outside of Chicago. In spite of
this chilly start to day, sunny skies and a moderating airmass
will allow inland temperatures to rebound back well into the 60s
to around 70. However, closer to the lake conditions will
remain cooler for another day (temperatures in the upper 50s to
around 60), as lake breeze influences result in onshore flow
this afternoon.

Dry weather is expected through the day today. However,
scattered rain shower chances will return to the forecast late
tonight into early Friday morning as the first of several mid-
level impulses ejecting out of the southwest CONUS begins to
move into the central CONUS. Overall, the best rain chances
(50%+) late tonight through early Friday morning will be across
west central through east central IL. Farther north and east
into the Chicago metro area, we are only looking at the
possibility (20-30% chance) for a brief period of light showers.
This activity should shift out of the area by mid-morning on
Friday, with dry conditions forecast the remainder of the day.
Even warmer conditions are anticipated Friday as breezy
southerly winds (gusting 25-30 mph) set up during the afternoon.
Accordingly, temperatures are expected to peak in the 70s, and
the the offshore wind component will result in the warmth making
it all the way to the Lake Michigan lakeshore.

The larger scale weather pattern will transition more quasi-
zonal (west-to-east flow) for a period to start the weekend,
before the next upper trough digs into the western CONUS later
in the weekend, fostering a shift to southwest upper-level flow
early next week. The net result of this will be return to
periods of active weather (showers and thunderstorms) this
weekend through early next week. While this is the case, it will
not be storming constantly across our area. In fact, we are
likely to experience a lot of dry time this weekend, so it will
not be a wash-out by any means. Shower and storm chances will
begin to return to the forecast Friday night into Saturday
morning, as thunderstorms developing west of our area in
association with an approaching mid-level disturbance later
Friday attempt to shift towards our area later Friday night. At
this time, the severe threat in our area with this activity
through early Saturday morning is low, owing to the poor
diurnal timing.

More scattered thunderstorms will be possible Saturday
afternoon as a surface frontal boundary sags into the area.
However, it is possible that the primarily focus for these end
up across the southern half or so of the area following any
early morning activity pushing the effective surface boundary
farther south. If this ends up being the case, capping and
little focus for renewed development farther north could result
in a mainly precipitation free afternoon across much of far
northern IL.

Later in the weekend into early next week, an upper-level
trough will dig across the western CONUS, fostering continued
periods of active weather from the Plains and Midwest through
the western Great Lakes region. Several waves of showers and
thunderstorms will be favored in this pattern, particularly west
and northwest of the area (on Sunday) as Gulf moisture surges
northward in advance of an elongated region of surface low
pressure extending from the central Plains northeastward into
the upper Midwest. Locally, shower and thunderstorm chances will
continue Sunday into early next week, but our best shot at a
higher areal coverage of showers and thunderstorms (some
potentially severe with instances of heavy rainfall) looks to
come Monday into Tuesday in association with an approaching
surface cold frontal passage. Confidence on the timing of this
front shifting into our area remains low, owing to large
ensemble spread.

KJB

&&

.AVIATION /12Z TAFS THROUGH 18Z FRIDAY/...
Issued at 627 AM CDT Thu May 14 2026

High pressure currently over northern Illinois will shift east
today, allowing WNW/NW winds under 10 knots to gradually favor
NE by late morning. A lake breeze will then shift winds E around
10 knots early in the afternoon for ORD/MDW. At RFD, winds will
remain generally S this afternoon. For all terminals, expect
winds under 10 knots to settle SE by late evening, then veer SSE
to SSW while beginning to gust over 20 knots around and shortly
after sunrise Friday. Winds will remain SSW with gusts up to
around 25 knots mid morning into the afternoon.

VFR conditions are expected through the period. Decaying mid-
level SHRA may cross or pass just south of the terminals around
sunrise Friday.

Kluber

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

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